It is well known to span a gap be providing a cantilever on each side of the gap, the cantilevers being of equal length and meeting at their free ends. It is inevitable that when a load is applied to the cantilevers, the stresses at their encastres will increase. Consequently if high loadings are to be expected, the encastres must be of substantial construction in order to withstand the resultant stresses imposed upon them. However, such substantial constructions may impose undesirable weight penalties on the structure involved.
A typical situation where these conditions occur is in an axial flow gas turbine engine having shrouded aerofoil blades. Each such aerofoil blade is provided with a shroud at its radially outer end (in relation to the axis of rotation of the gas turbine engine) so that the shrouds of adjacent aerofoil blades cooperate to define a duct which contains the gases passing in operation over the aerofoil sections of the blades. The shrouds are only supported by their respective aerofoil sections and therefore constitute centilevers. The loads imposed upon the shrouds by the gases are high and consequently their positions of attachment to their respective aerofoil sections must be strong enough to withstand the resultant stresses. However, structure providing such strength usually results in an undesirable weight increase in the shrouded aerofoil blade.